So you basically want the magnum to be better than the BR and DMR? That's just plain stupid, I'm sorry but your argument about it being just barely viable is completely false as the magnum with its extended range can easily outclass a BR even though it is supposed to be the better weapon just like the DMR. I just can't this seriously. All I get from this is simply that you want to be rambo and force people into playing around the fear they will be taken done by rambo with his god magnum. I played Halo CE, and I played Halo five, two completely different sandboxes, completely different mechanics, completely different time period and you want to implement these changes in for what? To relieve the time of the god magnum? Please, we already have the CE magnum in this game and even though it shoots slower, its pretty powerful weapon, outclassing most weapons including precision which is a strong indicator of how things would go. I'll stop ranting but seriously, just no, as much as I hate halo 5 and the weapon balance I would rather not unbalance everything with a god tier magnum.
But unto your DMR suggestion. Its fine, leave it, unless it becomes a two shot because of its decreased fire rate then no as this game would allow just about everybody who gets hit once by a slow firing DMR to run away.
For your automatic suggestions......I give up....just no......just......no.